1. Statement of the Technical Field
The present invention relates to artificial airways and more particularly to an airway device for controlling respiratory secretions in artificial airways, and associated devices such as respiratory gas delivery devices.
2. Discussion of the Related Art
The use of artificial airways is a common method of maintaining an open airway for patients who require some type of respiratory assistance. Artificial airways come in a variety of options depending on the patient and level of respiratory intervention required. Large numbers of artificial airways have three common features. First, the artificial airway will be a flexible tube that extends into the patient's trachea. Second, most artificial airways will have an inflatable cuff near the distal end of the tube. The inflatable cuff can be used to make an airtight seal, e.g., for nasal tracheal, oral tracheal and tracheostomy tubes where the entire breath of the patient is directed through the tube. Third, the standard artificial airway has a 15 mm fitting on the external opening of the tube to which respiratory gas delivery devices and instruments can be attached compliant with the ISO 5356; Anesthetic and Respiratory Equipment—Conical Connectors standard.
One of the common issues with having the patient breathe through these artificial airways is that respiratory secretions, which would normally enter the pharynx and be swallowed, expectorated or coughed out through the mouth, are forced to egress through the lumen of the artificial airway. The presence of the tube, being a foreign object in the airway can also stimulate respiratory secretions.
Keeping the tube and airway clear of secretions is a procedure performed by clinicians, which requires training and vigilance. Depending on the condition of the patient, the frequency of clearing the airway with a suction catheter varies greatly. When secretions accumulate in the tube there is added resistance to breathing and when the patient is strong enough, a forceful exhalation sends the secretions out through the tube and into the room or into any device attached to the tube.
Some fluid trap devices for use between an artificial airway and respiratory gas delivery devices, such as a ventilator circuit, have a fill volume substantially independent of orientation of the trap within the fluid circuit. Such fluid trap devices are disadvantageous as they impose unnecessary and excessive dead-space (e.g., exhaled air that is re-breathed) to achieve the independent orientation.
Typically, when a ventilator circuit or an instrument is detached from an artificial airway, the patient coughs and respiratory secretions and fluids are sprayed into the room. In addition, it is common for a patient on a ventilator to have secretions accumulate inside an artificial airway, such as endotracheal (ET) tube, with no place to go but up the tube, down the tube or into whatever breathing instrument is attached to the ET tube.
In the last decade, the use of “closed suction” devices with ventilator breathing circuits has become a standard at many medical facilities. A closed suction device allows for access to the airway with a suction catheter without detaching or removing the treatment device from the artificial airway. Closed suction systems add additional support to clinicians by greatly reducing the time and effort necessary for clearing the airway. A closed suction device for example, can allow a catheter to advance into the artificial airway for suctioning and then be withdrawn into a protective sheath where it is protected from contamination when the catheter is not in use. The closed suction catheter may be used multiple times without opening the device to the atmosphere, and is usually used for one to several days. A closed suction system allows access to the ventilator breathing circuit connected with the patient to remain “closed” as opposed to methods that require it to be “opened” to the atmosphere for access. Closed suction also reduces risk of microbial contamination of the artificial airway during suctioning thereby protecting the patient's airway from infection. In numerous medical institutions, the infection control departments have made the use of closed suction a standard of practice by requiring that all intubated patients in the intensive care unit (ICU) have a closed suction system installed.
Most clinicians find that there are a significant number of instances when it is necessary to detach a ventilator circuit or respiratory instrument (i.e. “open the circuit”), and having protection from patient secretions entering the environment during these occasions is most desirable.
There are three main problems with secretions in the tube of an artificial airway. First, when the ventilator circuit is disconnected, secretions can be sprayed into the room if the patient coughs. Second, secretions in the artificial airway result in compromised breathing. Third, when secretions are forced out into the attached ventilator circuit, these secretions can foul the attached instruments, such as a heat and moisture exchange (HME) device, and the like.